1. Field of the Invention
The present invention relates to a composite communication system, and more particularly to a method of providing a public network service when a call management device is in a down state in a wire and wireless composite communication system serving through a wire terminal and a wireless terminal by connecting the wireless network to an extended network linked to the public network.
2. Description of the Background Art
The wire voice communication service in an extended area is generally served through a private branch exchange (PBX) or a key-phone system, while the wire data communication service is served through a local area network (LAN) switch and a router using a server and the like. The wireless communication for the extended communication is served by using cordless telephone generation 2 (CT-2), but the handoff function is not supported when the call is linked to a public network. Meanwhile, even if the communication providers are different from each other, the communication service between the wireless terminals is available regardless of a limited area such as the extended area and the service is served with a charge. The wireless communication in the extended area that are limited by a specific area could not be served at present in the field. The cordless telephone generation 2 technique, which served in the Republic of Korea for a while, and global system for mobile communication (GSM) technique of Europe were introduced in part as similar techniques.
However, there is a drawback that the composite communication system allowing the wire and wireless communication is not efficiently provided for in the field. The composite communication system allowing the wire and wireless communication will require that a technique for performing the public network service to complete a call when the call management device of the private wireless network is in a down state.
Exemplars of the art are U.S. Pat. No. 5,995,831 issued to Gulliford et al. for Cellular-Telephone Central Call-Processing System Utilizing Object-Oriented Software In Adjunct Personal Computer, U.S. Pat. No. 5,966,649 issued to Gulliford et al. for Cellular-Telephone Central Call-Processing System Utilizing Object-Oriented Software In Adjunct Personal Computer For Generating Billing Records, U.S. Pat. No. 5,995,598 issued to Berstis for Phone Line LAN, U.S. Pat. No. 5,845,211 issued to Roach, Jr. for Wireless Digital Network, U.S. Pat. No. 6,034,950 issued to Sauer et al. for System Packet-Based Centralized Base Station Controller, U.S. Pat. No. 5,184,347 issued to Farwell et al. for Adaptive Synchronization Arrangement, U.S. Pat. No. 5,243,642 issued to Wise, Jr. et al. for Telephone Call Management Device, U.S. Pat. No. 5,625,866 issued to Lidbrink et al. for Mobile Telecommunication System Having An Auxiliary Routing Arrangement, U.S. Pat. No. 5,557,606 issued to Moon et al. for Routing Of Voice Communication At A Cell Site In A Land Mobile Radio System, U.S. Pat. No. 5,633,868 issued to Baldwin et al. for Virtual Circuit Management In Cellular Telecommunications, U.S. Pat. No. 5,303,287 to Enrique Laborde entitled Integrated Personal/Cellular Communications Systems, U.S. Pat. No. 5,890,064 to Ina Widergen et al. entitled Mobile Telecommunications Network Having Integrated Wireless Office System, U.S. Pat. No. 6,073,029 to Dennis C. Smith entitled Method And System For Providing Wireless Communications To A Subscriber Of A Private Wireline Network; and U.S. Pat. No. 6,097,966 to Donald V. Hanley entitled Wireless Access For Local Exchange Carriers, U.S. Pat. No. 5,506,887 to Emery et al. entitled Personal Communications Service Using Wireline/Wireless Integration, U.S. Pat. No. 5,715,296 to Schornack et al. entitled Concurrent Wireless/Landline Interface Apparatus, U.S. Pat. No. 5,715,296 to Schornack et al. entitled Concurrent Wireless/Landline Interface Apparatus, and U.S. Pat. No. 5,873,033 to Hjern et al. entitled Method And Arrangement For Transfer Between A Cordless Telecommunication System And A Cellular Mobile Telecommunication System.
It is, therefore, an object of the present invention to provide a method of providing a public network service when a call management device is in a down state in a private wireless network within a wire and wireless composite system availing extended communication.
It is another object to have a highly reliable and efficient wired and wireless communication system.
It is yet another object to have a communication system that will function even when the call management device is in a down state.
It is still yet another object to have a method of determining whether a call management device is in a normal state or abnormal state.
To achieve the above objects, there is provided a method of providing public network service when a call management device is in a down state in a private wireless network. The private wireless network has a base station controller (BSC) for performing a radio link control and a handoff functions, a base station transceiver subsystem (BTS), linked to the base station controller, for constructing a wireless communication path with at least a mobile station which belongs to a cell area of the base station transceiver subsystem and managing radio resources, a private branch exchange (PBX), linked to the base station controller and a local area network (LAN), for performing an origination and termination communication and extension communication and providing a message communication with a call message using an info-link message and voice over Internet protocol (VoIP) function, a call management device for providing private resource management (PRM), program loaded data (PLD) loading functions of a processor which controls wireless calls and services, maintains and repairs the wireless resources, and the base station controller (BSC) resource, for controlling wire and wireless composite functions and supporting a corporate wireless short message service, and for providing a visitor location register (VLR) management function for wireless terminal roaming function between short message service(SMS) web server and the private branch exchange (PBX) and registering corporate wireless subscribers and establishing predetermined functions. The method includes periodically checking, at the base station controller, a state of the call management device, and performing the wireless public network service when the call management device is in a down state.